1. Field
Embodiments relate to a light emitting device.
2. Description of the Related Art
A light emitting diode (LED) is a device which converts electric signals into light using characteristics of compound semiconductors. LEDs are now being applied to devices such as home appliances, remote controls, electronic signboards, displays, a variety of automatic appliances and the like and their application range continues to expand.
Generally, a miniaturized LED is fabricated as a surface mount device such that it can be directly mounted to a printed circuit board (PCB). Accordingly, an LED lamp used as a display device is also developed in a surface mount device-type. Such a surface mount device may substitute for a conventional lamp and is used as lighting displays, character displays, image displays and the like, rendering various colors.
LED semiconductors are grown on a hetero-substrate made of sapphire, silicon carbide (SiC) or the like, having a hexagonal system structure by a process such as metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).
When a semiconductor layer is formed on a support substrate, cracks, warpage or dislocation may occur in the semiconductor layer due to differences in lattice coefficient and coefficient of thermal expansion between the semiconductor layer and the substrate. Accordingly, there is a need to reduce stress caused by differences in lattice coefficient and coefficient of thermal expansion between the support substrate and the semiconductor layer.